# Two STK amps on one system

#### DanielKaaos

##### Newbie level 4
Hello all!

I have Sony RXD system and two STKs. One is STK407-090E and the other one is STK407-100. On both STKs the right channels are blown up. Can I (theoretically) connect the two amps in stereo mode?

Thank you!

##### Super Moderator
Staff member
If they work okay otherwise then you can have stereo by putting one channel through each unit, yes.

Make sure you minimize volume through the blown channel. There's a chance the output stage was not designed to be operated without a load. This assumes you leave it with no speaker attached.

### DanielKaaos

points: 2

#### KlausST

##### Super Moderator
Staff member
Hi,

I'd say a defective audio amp channel may act rather random.
Low current, high current, overheating, oscillating....

Thus I'd not use the defective STKs.

Klaus

### DanielKaaos

points: 2

#### DanielKaaos

##### Newbie level 4
If they work okay otherwise then you can have stereo by putting one channel through each unit, yes.

Make sure you minimize volume through the blown channel. There's a chance the output stage was not designed to be operated without a load. This assumes you leave it with no speaker attached.
They both work Okay separately on the Sony system when I disconnect output of bad channel from the STK, otherwise POWER PROTECT appears on the display.

Thank you!

##### Super Moderator
Staff member
otherwise POWER PROTECT appears on the display.
Is this an alert telling it must shut off circuitry to reduce overmuch current in the output stage?
A speaker can be destroyed by one burst of high current AC or DC. A speaker can be destroyed by ultrasonic oscillations which we can't hear.

It's starting to look as though it's not worth the risk to use the faulty STK's. An internet search reveals they are IC's which cost only $5. #### DanielKaaos ##### Newbie level 4 Is this an alert telling it must shut off circuitry to reduce overmuch current in the output stage? A speaker can be destroyed by one burst of high current AC or DC. A speaker can be destroyed by ultrasonic oscillations which we can't hear. It's starting to look as though it's not worth the risk to use the faulty STK's. An internet search reveals they are IC's which cost only$5.
Yes, that's what this message means. There is relay that shuts off the path to speakers when this happens.